#include<stdio.h>
#include<math.h>
int main()
{
	double a, b, c, s, r;
	while(scanf("%lf %lf %lf", &a, &b, &c)==3)
	{
		if (a==0||b==0||c==0)
			printf("The radius of the round table is: 0.000\n");
		else{
			s=(a+b+c)/2;
			r=sqrt(s*(s-a)*(s-b)*(s-c))/s;
			printf("The radius of the round table is: %.3lf\n", r);
		}
	}
	return 0;
}